Adams Simulation of Hose Routing Helps Reduce Time to Market by Six Weeks

Company:

Navistar & Tech Mahindra

Products:

Adams

Industries:

Automotive

Overview:

It takes a 450 horsepower truck with an 80,000 lb. load roughly 90
seconds to accelerate to 50 mph but the brakes must be able to
stop the truck in less than 5 seconds. Air brakes are used almost
exclusively in heavy-duty trucks and trailers because they offer
the following advantages. First, the air they run on is free. It only
needs to be compressed, cleaned, stored and distributed. The air
brake circuit can be easily expanded so trailers can be coupled
and uncoupled from it. Besides providing the energy required to
stop the vehicle, compressed air also signals when and with how
much force the brakes should be applied in any situation. Finally,
air brakes can be designed with sufficient fail-safe devices to
bring the vehicle safely to a stop, even in the event of an air leak.
Reinforced rubber hoses deliver air from fittings on the frame to
brake chambers on the axles. In a typical tandem rear suspension
there are typically 8 brake hoses plus additional hoses for the
power differential lock and other features for a total of 11. The
hoses must be routed through a tight space and accommodate
the full range of steering gear and suspension travel. The hoses
are required to avoid contact with components with sharp edges
that might wear the hoses, maintain a specified minimum bend
radius to avoid constricting flow within the hose, and avoid
axial forces high enough to pull out the hose out of the fitting.

Results Validation:

“Simulation makes it possible to try many
different positions, orientations, and
clipping options early in the design phase
prior to the availability of a prototype,”
said Stefano Cassara, Manager Vehicle
Dynamics Simulation for Navistar. “New
design iterations can be evaluated in a small
fraction of the time required for physical
testing. The new approach makes it
possible to design new hose configurations
in only about two weeks. Since the design
process will be carried out early and outside
the critical path we should be able to bring
new vehicles to market six weeks faster
than in the past. Another advantage of the new approach is that we can model
loading scenarios, such as braking, that
cannot be duplicated on the test rig.”

Benefits:

Simulation of hose routing helps
reduce time to market by six
weeks

Adams predictions perfectly
matched test results in each
steering position

Simulation provides a much better
understanding of how to route the
braking hoses to avoid contact
with components with sharp
edges that might wear the hoses
in response to suspension and
steering movement

New Adams FE Part provided a
fast and accurate way to predict
the large deformation of brake
hoses in Adams environment